Hollow Wooden Surfboard - My Magic Carpet

Introduction: Hollow Wooden Surfboard - My Magic Carpet

Welcome to my first instructable. I've made a few wooden surfboards so thought I would share my favourite. It's 7'6 x 21" x 2"3/4 magic carpet design, a mellow cruiser good for lazy days and lazy waves.

Step 1: Glue the Pattern to the Plywood

So, there are places online where you can buy the plans, or you can design your own. I use a program called AKU. Using this you can create designs pretty quickly. For wooden boards you need to create slices every 150mm that define your ribs. The central spine is the side profile. The outline is your final planshape. Think of it as a fishbone with a spine and ribs that you then build the decks and rails around. I then use a program called hollow board template maker that generates a PDF of the spine, ribs and outline. Print out at full size and using spray mount stick onto 4mm plywood.

The whole build thread is here: also, with lots of cool surfboard projectshttp://www.grainsurf.com/forum/viewtopic.php?f=11&t=5532

Step 2: Cut the Frame

I use a bandsaw to cut out all the frame parts, then dry fit it together. As the design fits onto a 1200x2400mm sheet you can get the frame and the whole bottom deck out of one piece of ply. Sit the frame onto the bottom deck and draw on the rib and spine positions. This is your guide for where a bead of PU glue will go. For this build I used little blocks of balsa wood that keep the frame straight and the ribs 90deg to the spine.

Step 3: Glue the Frame to the Plywood

I made a clamping frame using 3x2 timber, threaded bar and some nuts and penny washers. You'll see how it works but the idea is the board is clamped every 200mm between two strips of ply that can be adjusted to fit the top and bottom rocker of the board using the threaded bar and some nuts. Bead the PU glue onto the bottom deck, fit the frame and clamp in place.

Time taken so far about three hours - relax till tomorrow while the PU glue cures.

Next add the chine strip - 6x6mm stripwood. This glues into place into notches cut on the rib ends and gives you the outline shape. I'll add the rail strips next, but first some hardware considerations.

Step 4: Fin Box Support

At the tail of the board I add some scrap foam floor insulation blocks. These form support for the finbox and the leash plug when they get holes routered in place and glued in later on. There is also a vent to fit to the frame - for this I use a brass insert pressed into a wooden block then glued to the spine to fit flush with the underside of the deck. As the board is hollow, the air inside can expand and burst the board on a hot day. Using a vent means you can equalise the pressure so the board doesn't suck air in or blow! The vent will be sealed up with a brass bolt and rubber washer.

Step 5: Cut and Glue the Deck

Next I cut the strips for the top deck. These need to be 6mm thick and ideally longer than the board so no scarfing needed. I used some reclaimed western red cedar and pine. The nail stains will look good. The strips can be edge glued using titebond 3 and masking tape. I glue up in twos and threes - no need to do the whole deck in one piece.

Step 6: Rail Strips

Cut some 6x6mm and 6x12mm strips - these get glued to the ends of the ribs to form the rails using any clamping method you can use. Like the drainpipe clamps? Cut an inch off a drainpipe, cut a slot and you have a clamp. I have a box of about 40. You need a lot of clamps for rails. Glue up one strip at a time, using a plane to bevel the strips and taper at the ends. PU glue helps full any gaps you have.

Step 7: Top Deck

Now we add the deck, a strip or two at a time. You need to trim each deck panel to fit against the rails using bandsaw and plane. Glue using PU and don't forget about the vent!

Step 8: Ready for Final Shaping

Once you have it all glued up and cured its ready for shaping. The deck strips take about four or five days to shape and glue. Reckon on an hour or so per panel plus overnight cure time. Now comes a lot of sanding - I use a belt sander and take care to work evenly around the board. Step back and eyeball regularly to keep it symmetrical. Measure, look and measure. This is also the time when you realise the board rattles and you can't find you pencil.

Step 9: Seal the Top

Here's where it gets a little crazy. I seal the top deck using resin research epoxy having masked out the rails. I'm going to do a Mexican blanket resin job on the bottom (crappy ply) and leave the wood exposed on top. This is where the colour of the grain POPs and you see what you have. The positive negative stripes have come out well.

Step 10: Glassing

I have my design worked out and taped to the wall. I add a layer of 4oz fibre glass weave to the bottom and tape in place. The top is masked out. Next I mix up the pigments and resin batches. I'm using polyester resin so add 5ml pigment into 100ml resin and mix well. Do not add catalyst yet! Put gloves, respirator and goggles on, get your squeegee ready and catalyse the first colour. Pour across on bands, then choose the next colour and repeat.

Step 11:

Step 12: Glass the Top

Trim the rail laps with a very sharp blade when the resin loses its tack but is not fully cured. Leave overnight to cure then glass the top. I've added my pinlines (vinyl car stripes from eBay and they are self adhesive) and logo laser printed onto rice paper and laid under the glass. Leave to cure then gloss coat both sides. Polyester resin again but adding wax in styrene so it cures smooth and non tacky. You'll see I already fitted the leash plug and sealed up level with plasticine before glassing - you can open these up afterwards with a Dremel.

Step 13: Pinline and Finbox

Add the pinline before the gloss then router out the finbox slot. The finbox gets glued in with a paste if fibreglass and resin. For the leash plug use a forstner bit and glue in the same way.

Now just the sanded finish to do - wet and dry paper from #400 right up to #1500 and we're done.

Finbox - this must be central soyou must cut into the stringer. However, as you will have put support blockseither side then this means you have plenty of material to glue the finboxinto. I put it 140mm from the tail of the board so the finbox would be incontact with the underside of the top deck at the tail. It should be a tightfit. Roughen the glue surfaces of the finbox then mix up a thin paste of epoxyplus wood flour (from a sander - peanut butter consistency when mixed), spreadinside the hole and on the finbox and push into place. You may need to hold itwith a couple of clamps rather end of a strip of wood running across the board.Place a fin in the box and check it sits vertical... you can see I made asimple router jig and used the collar on my router plus the cutter size to workout the dimensions of this. Go careful with the cut depth and measure carefully- the last thing you want to do is burst through the top deck of the board.Measure the finbox depth and check in relation to the board. The plastic tabs on the finbox help set the depth, then you sand all this down after glassing (or even before - I usually sand the finbox first then glass over the top to ensure a good seal but if I ever knock a fin and rip out the finbox then it means a full re-glass. Remember to tape over the fin slot if you do this method).

Vent is a little easier -make up a block (I use something like 15mm ply and about 50x50mm). Drill andfit the vent into this. The vents I use are brass threaded inserts and aresquare so drill a hole then chisel square. Use a bit of epoxy peanut butter tobond it in to the block. Then glue the block to the stringer and a rib at thenose of the board. anywhere in the first foot of length of the board so up against the second rib is a good place. This means the vent is off centre. Measure where the vent iswhen gluing on the deck planks (you can see my marking lines on the plank over the vent), transfer the position to the deck plank then drill a small pilot hole so that the board is vented. Prior to glassing I fill this hole up with plasticene or blue-tak and glass over the top. Then after glassing drill a hole say 12mm in the plank so that when this plank is glued inplace it sits directly over the vent. Make user all ribs and stringer have beendrilled so all compartments can breathe. You could fit the vent into thestringer if you want it central - you just cut a pocket for the vent to sit inbut you will have to support either side. This pocket has to be deeper than thevent so that it can breath. Remember though at the nose the stringer is pretty shallow so can easily snap...To seal it use a stainless or brass bolt witha rubber o ring. Make sure your surf bag or fin bag has an Allen key that fitsthe vent or you could use a hex-bolt and cut a slot in the head so it can be coin operated.... I have burst a board in the UK when forgetting to open up the venton a warm day so never skip the vent...

As promised some pictures of my build - its almost done. I started with a home-made EPS core with wood stringer, covered with a 3/32" plywood and poplar rails. rattle-can paint with paint-pen artwork, and futures fin boxes. I also expanded the dimensions from 7'6" to 8'. one picture is before fin boxes, the other is while letting the epoxy set on the bottom.

thanks, I have the 7'6", what i'm concerned about the rocker dimentions. The nose rocker only looks to be about 2.5", is this correct? as a longboard is typically in the 3.5"-5" range. and the tail rocker is about the same as the nose..

at this point I plan on mixing it up a bit. so I won't have to put in a pressure valve, I am planning to shape a xps 1# blank with a wood stringer & "shell". expanding the plans from 7'6" to 8' for more volume for my larger size. perhaps a few yards of a nice cotton material with a print in the epoxy. i hope the low weight xps should not matter with a tough wood/epoxy shell. lets see what happens....

Wooden blocks fine for the fins. Check the pictures for how I do my vent - I make sure the vent block is glued to the sound and a rib.

Wet sanding by hand keeps the dust down. Also, regarding clamps- I've seen people use bike inner tubes, bungees and straps. The main thing is that you squeeze the rail strips together and to the rib. Good luck!

Just giving a progress update, Im working with what I have, I dont have a clamping rig or that much time to build one nor do I have access to 40+ clamps, so I am improvising. My next question is how do I make support for the fins? I dont know how to get my hands on blocks of foam, I have some wood I can use and just glue it to the bottom of the board and then router in a slot for the fins when I finish the rails and the top. Any suggestions on fin/vent support in the board so that I dont accidently hit the fins the wrong way and it cracks the fiberglass because there is no support for them?

Also you mentioned when the glass hardens, sanding it becomes an issue for breathing without a respirator, is it still bad for your health if you sand it by hand like without a power sander, but instead with a sanding block?

Thanks again for these responses, Im very excited to eventually use this board!!

This is my progress so far, I have yet to glue the skeleton together but so far its not looking too bad. My next question is about the fiberglass/resin application. I have never worked with those materials so im not sure how to do it properly, do you know of any tips/youtube tutorials that could show me the correct way to do it? Also Im worried about the vapors, I will probably be working in the garage which has poor insulation so Im concerned about the toxic fumes seeping into the house in the rooms close to the garage. Is there something I should do to prevent this? Or should I do the application outside?

Thanks again for the response, and also I think some other comments were asking about how to print the plans full size? The way I did this was to open the downloaded PDF in Adobe Reader, and then go Print>Poster and then print it under that tab. There are other ways to do this, its called 'Tiled Printing' apparently.

Looking great! it will be easier to glue up the frame once you cut the outline profile and add the support blocks to line up everything. I used 4mm ply and square section balsa. Take care here to get the centre line straight and the ribs at 90degrees to this = I used a big try square and measured to make sure it was symmetrical.

I get all my glassing materials from Seabase in the UK - 4oz cloth and epoxy resin. There are no real fumes from epoxy but wear gloves as some people can get an allergic reaction. The dust from sanding hardened resin will need mask protection too. You will need to make some stands (check youtube "Grain Surfboard Laminating Tutorial with Entropy Resins" for the process and to see the stands ). I wouldn't recommend using polyester resin - this stinks and you would need a respirator. Outside means dust and flies in the lamination = not good! There are resins that cure instantly with UV light too but I have not used these.

I love glassing - 700g resin per lamination coat then about half that for the fill coat. My tip for a first timer would be to use a little masking tape to hold the glass in place and work from the centre out to the rails. I masked out the top of this board as I was using colour on the bottom - this gives you opportnity to mark out where you will cut the lap. Laminate the bottom, wrap around the rails, then repeat for the top. Take care to get your laps neat. Watch a lot of youtube videos to suss the technique then watch some more. Watch how the rails are done, and you need a sharp blade to trip the lap before the resin fully cures. Epoxy resin work needs a warm, dust free environment so I did my first board in the house. Plastic sheeting on the floor and got the room up to about 25 degrees C.

Hi there! Knot free wood is best for the rails - softwood or hardwood will do, or even balsa. At 6x6 they should bend, or you can use steam (an iron and a wet cloth) to soften them. You will need tots of clamps - spring clamps, g clamps or home made pipe clamps (check out the pictures). Apply the clamps to close up the gap so you end up working at funny angles.For solid fins you will need to build some support inside, under where the fins will be. Some builders router a slot into the deck and glue the fins in. Glassing the fins in gives them strength - YouTube glass on fin installation.For a vent any non corroding insert plus a bolt will suffice - I got mine from a company that makes brass inserts for injection modules parts. Then used a stainless Allen bolt with an o ring. Good luck! Mike

I really want to try and build this, but Im having some difficulty with how to put the rails together. What type of wood do you use for the rails (dimensions like 6mm x 6mm) and how do you use the clamps to glue it together?

I also am curious about how I would give the board permanent wooden fin(s) without using a finbox?

Also also, is there a way to have a makeshift vent instead of buying one online? Like using a brass fitting and a screw to manually cover it?

Thanks again for this post its really helpful, I'm trying to follow it strictly.

Hi Peter, stoked you are building one - you are right, the tail block and noseblick are improvised using the outline template - - the outside shape matches this, and the inside shape is about 20mm inside. Good luck, and post pictures! mike

Hi! I am trying to make it myself and i didnt find any plans for the nose and tail blocks. Did you improvise it or had some kind of template? And if you made it with a template, could i have it? -Peter

I made this as a quick project for a show just as wall art. Thanks for the plans! Very nice looking board. I plan to make a 'proper' surfable board now i have more time to spend on the project. The back of the board is made with all my little scraps and off cuts in an abstract design. Cheers, Lisa.

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Not had any issues in 8 years with the polyester in the lam. You need the kick from polyester to stop the colours blending too much before it cures. Epoxy is nicer to work with and adheres better to oily wood like cedar. Solarez would be interesting to try with colour but no availability in the UK. What experiences have you had with polyester? I've only ever had one issue and that was it not adhering to oily wood and never had a delam on plywood.

View in Adobe Acrobat, and view at 100% then print current view - scroll across then print current view again. Repeat all the way across, then scroll down and away you go again. I'm sure there are better ways or other pdf viewers that let you print them out but the way I've described works for me! Hope that helps

Hi Mike. This is stunning! How do you print out the pdf template on seperate a4 sheets? I open up the plan and all comes up and prints out on one a4 sheet. Which could make an awesome tiny board, but it certainly wouldn't float me.

The board gets heavier meaning a bit more weight to paddle, so once you get going the weight isn't really noticeable. I add a bit more volume in the center to compensate the extra weight. Balsa is good as long as you support the planks, as is poplar. Western red cedar is good too. Paulownia is good if you can get it - I built a paulownia 9'6" that weighed 16lbs... They do have soul, a resonance in the water, and better still, even if you a crap surfer like me, you know you are riding something truly unique!!!

You can make nose and tail templates from the outline view - just remember to fold your paper in half so they are symmetrical. Print out the template and trim to outline, then you can use about 200mm from each end to make the blocks.